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A Corn Belt Insect Threat: Western Bean Cutworm

Categories: GROWING, CORN

Native to North America, western bean cutworm (WBC) is becoming a severe pest in several areas of the Corn Belt. Although it is traditionally a pest of the Western Great Plains, WBC has moved east, inhabiting much of the Corn Belt. While populations may vary year to year, this corn pest is a consistent threat in many corn growing regions. Masses of up to 200 eggs are laid on plant leaves and mature quickly over a few days. Unlike corn earworm, WBC is not cannibalistic, so it is common to find multiple larvae feeding on 1 ear. 


Photos by Charles Scovill, Golden Harvest Agronomist​​​​​​​

Scouting and treatment
WBC infestations are often patchy and may occur over a several week span, requiring multiple scouting visits and creating challenging treatment decisions. There are multiple scouting options, including setting pheromone and/or black light traps, using degree days to predict moth emergence and monitoring corn plants. When scouting corn, check 20 plants in at least 5 areas, and look for egg masses in the upper 3 or 4 leaves. Egg masses can be hard to find, and proper treatment timing difficult due to varying egg mass maturity, so the application window is critical. After WBC larvae enter the ear, insecticide applications aren't effective.

The WBC infestation window occurs mid- to late-July, with potential feeding throughout the season.​​​​​​​

Crop damage

Young larvae feed on corn tassels, pollen and silks, then chew holes through the husk and devour developing kernels, as pictured below. Larval feeding affects corn yield and quality, making kernels susceptible to mold and mycotoxin development. Such kernel quality degradation can negatively affect the grain price and potentially be harmful to livestock.

Agrisure Viptera® (left) versus ears from hybrids without Agrisure Viptera (center and right) under WBC pressure.​​​​​​​
Protect your hybrids
When making seed selection decisions, keep in mind Agrisure Viptera is the only trait available today that effectively controls WBC. Available through Golden Harvest hybrids, Agrisure Viptera is the best option on the market to consistently limit WBC damage and protect grain quality. By controlling major leaf-, stalk- and ear-feeding corn insects, including WBC, Agrisure Viptera trait stacks offer better crop stand and lower levels of disease, resulting in increased yield and profit potential.

Contact your Golden Harvest Seed Advisor with questions or for additional agronomic insights.

Photos are either the property of Syngenta or used under agreement.

Syngenta hereby disclaims liability for third-party websites.

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